Recent research, now on the verge of publication, on the history of concepts of heart failure, shows that valuable information, available nowhere else, exists in the consultation reports of Marcello Malpighi. This is because Malpighi did not publish anything on clinical medicine, althoguh he engaged in clinical practice on hospital wards, as physician to popes, and as consultant. His consultation reports reveal that, at an early date, he had managed to understand part of the mechanism of heart failure. There is a strong possibility that similar considerations apply to Malpighi's intellectual heir, Giovanni Battista Morgagni, who functioned chiefly as an anatomist and wrote on normal and pathol gical anatomy but also practiced as a medical consultant. His consultation reports are likely to furnish important information about his reasoning and his decisions in difficult clinical situations, and hence to illustrate the progress of clinical understanding. This study of a sample shows that this expectation is warranted.